Reptiles Flashcards
What are reptiles derived from?
A group of labyrinthodont amphibians known as anthracosaurs
Reptiles are a ________ group that gave rise to mammals and birds.
Paraphyletic
Together, mammals, reptiles and birds constitute a monophyletic group called ________.
Amniota
Name the four extant forms of reptiles
Crocodilians (crocodiles, gharials, caiman and alligators) DIAPSIDA
Sphenodontia (tuataras) DIAPSIDA
Squamata (lizards, snakes and amphibaenids) DIAPSIDA
Testudines (turtles and tortoises) ANAPSIDA
What does the cleidoic egg do?
1) acts as a self-contained environment for development
2) allows animals to bypass larval hatch as miniature adults
3) Shell and extra-embryonic membranes to prevent drying
4) Supply nutrients, water and oxygen
5) remove/store waste products
6) Terrestrial development of embryo without desiccation
Name the four extra-embryonic membranes in the cleidoic egg.
Allantois
Chorion
Amnion
Yolk sac
What does the amnion membrane do?
It encloses the embryo in a fluid-filled sac for protection
What does the chorion do?
It lines the egg shell and provides protection and allows for gas exchange
What does the allantois do?
Also important for gas exchange and provides a sac where nitrogenous waste is stored away from the embryo
What does the yolk sac do?
Contains yolk/nutrients as food for the developing embryo
What terms are used to describe egg layers and live-bearers?
1) Oviparity = egg layers
2) Viviparity = live-bearers
Reptilian skin is dry and scaly and minimises ______________.
Water loss
Name four ways in which a reptile tries to maintain body temperature.
1) Orientation
2) Contours
3) Colour
4) Blood flow
Name three advantages of being an ectotherm
1) Expend less energy
2) Requires less food
3) Fewer energetic constraints on body size
Name three disadvantages of being an ectotherm
1) They are less active in cooler temperatures and have to warm up in the sun which puts them at risk of predators
2) They are unable to increase respiration rates to increase internal heat
3) Biological functions constrained
Why can many reptiles not sustain running?
The muscles used for respiration are the same ones used for running, so during running respiration is impaired.
Amphibians have ______ occipital _______ and ______ cervical vertebra
Two occipital condyles and one cervical vertebra
Reptiles have _________ _________ condyles and __________ cervical vertebrae
One occipital condyle and two or more cervical vertebrae
What do the changes in the number of occipital condyles and cervical vertebrae between amphibians to reptiles increase?
Head mobility.
Describe amphibian skulls.
Flat and broad.
Describe reptile skulls.
Deep and narrow.
What do amphibians have that allows them to close their jaw rapidly and what type of jaw is this called?
They have a pair of vertically orientated muscles that close the jaw rapidly. This jaw is called a snap-trap jaw and allows them to swallow food whole with little or no food processing.
________________ process is absent in amphibians except for in ___________ _____________
Pterygoid process is absent in amphibians except for in advanced anthracosaurs.
The pterygoid process is present in reptiles and is a synapomorphy for _________ and ___________
Advanced anthracosaurs and amniotes.
The pterygoid process is associated with what?
The bifurcation of a single amphibian muscle into two muscles, the adductor mandibulae and the pterygoideus.
When does the adductor mandibulae exert its strongest force?
When the jaws are closed. It helps crush food and provides for increased food processing capabilities.
What is the term used to describe mobility within the head skeleton?
cranial kinesis
Snakes have lost their mandibular _________.
Mandibular symphysis
What is the mandibular symphysis?
A bony articulation joining the two halves of the mandible.
What feature allows the mandible to flex in snakes?
The intramandibular hinge
What are snakes closest living relatives?
Anguimorph and iguanian lizards.
Vision is usually adapted for ________ conditions, with _______ vision and more advanced __________ than in amphibians.
Vision is usually adapted to DAYLIGHT conditions, with COLOUR vision and more advanced DEPTH PERCEPTION than in amphibians.
The simplified snake eye suggests what?
Re-evolution of the eye
